KR101564374B1 - Method of preparing artificial graphite negative electrode material for rechargeable lithium battery and artificial graphite negative electrode material for rechargeable lithium battery prepared from the same - Google Patents

Abstract

A step of mixing the coke and the fine particles to obtain a mixture, a first heat treatment to obtain a carbide, and a second heat treatment of the carbide to obtain graphite, wherein the fine particle is a metal oxide, a metal hydroxide Or a combination thereof, wherein the metal comprises Ti, Ni, Al, Si, W or a combination thereof, and a process for producing an artificial graphite anode material for a lithium secondary battery and an artificial graphite anode material for a lithium secondary battery produced from the method .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial graphite anode material for a lithium secondary battery and an artificial graphite anode material for a lithium secondary battery produced therefrom. 2. Description of the Related Art Artificial graphite anode materials for a lithium secondary battery,

To a process for producing an artificial graphite anode material for a lithium secondary battery and an artificial graphite anode material for a lithium secondary battery produced therefrom.

Recently, lithium rechargeable batteries have become increasingly important in the IT mobile market due to the trend of smart phones and charge / discharge speed of batteries in HEV (hybrid electric vehicle) and ESS (energy storage system) Demand is high. Accordingly, there have been many studies on an anode material for a lithium secondary battery capable of meeting various demands such as high capacity, high output, high energy density, high discharge voltage, and output stability.

In the past, mainly carbon-based and graphite-based materials having an electrochemical potential as low as that of metal lithium were used mainly while reversibly receiving and discharging ions while maintaining their structural and electrical properties with a negative electrode active material of a lithium secondary battery come.

Especially for artificial graphite, the discharge capacity is 300 to 330 mAh / g, which is lower than 360 mAh / g of natural graphite. In addition, artificial graphite is inferior to natural graphite in terms of manufacturing cost since coal or petroleum coke is produced through heat treatment at 2500 ° C. or higher. On the other hand, in the case of natural graphite, surface carbon coatings of spheroidized natural graphite are generally applied, and their lifetime characteristics are lower than those of natural graphite. Also, in the case of artificial graphite, it is difficult to manufacture a high-density electrode due to the internal structure of the relatively dense particles. In the case of the natural graphite surface-coated product, the surface coating structure of the particles is broken during the production of the high- The edge of the graphite is exposed and the deterioration of the life characteristics tends to proceed.

One embodiment of the present invention is to provide a method for manufacturing artificial graphite anode material for a lithium secondary battery, which has a high capacity and a reduced manufacturing process cost.

Another embodiment is to provide an artificial graphite anode material for a lithium secondary battery produced from the method for producing artificial graphite anode material for a lithium secondary battery.

One embodiment includes mixing coke and fine particles to obtain a mixture; Subjecting the mixture to a first heat treatment to obtain a carbide; And a second heat treatment of the carbide to obtain graphite, wherein the fine particles include a metal oxide, a metal hydroxide, or a combination thereof, and the metal is selected from the group consisting of Ti, Ni, Al, Si, W, The present invention also provides a method for producing an artificial graphite anode material for a lithium secondary battery.

The coke may comprise an acicular coke containing less than 0.01% by weight of ash.

The average particle diameter (D50) of the coke may be 1 to 15 mu m.

The average particle size (D50) of the fine particles may be 1 to 45 mu m.

The fine particles may be selected from the group consisting of Ti ₂ O ₃ , TiO ₂ , TiO (OH) ₂ , NiO, Ni ₂ O ₃ , NiOOH, Ni (OH) ₂ , corundum (Al ₂ O ₃ ), diaspore α-AlO (OH)), boehmite (boehmite) (γ-AlO ( OH)), arc Ala child agent _{(akdalaite) (5Al 2 O 3} · H 2 O), gibbsite (gibbsite) (γ-Al ( _{OH) 3 + α-Al (} OH) 3), via light (bayerite) (α-Al ( OH) 3 + β-Al (OH) 3), SiO 2, Si (OH) 4, Si 2 O (OH _{) 6, Si 3 O 2 (} OH) 8, Si 4 O 3 (OH) 10, WO 2, WO 3, H 2 WO 4, (NH 4) 10 [H 2 W 12 O 42] · 4H 2 O or And combinations of these.

The fine particles may be mixed so that the atomic ratio of the metal element contained in the coke and the fine particles is 100: 1 to 100: 30.

The mixture may be obtained by further mixing a binder pitch, and the binder pitch may have a softening point of 40 to 250 DEG C and a quinoline insoluble content of 0.1 to 5 wt%.

The binder pitch may be 5 to 50 parts by weight based on 100 parts by weight of the coke.

The method may further include molding the mixture before the first heat treatment.

The first heat treatment may be performed at a temperature of 800 to 1500 ° C.

The second heat treatment may be performed at a temperature of 2500 to 2800 ° C.

And after obtaining the graphite, grinding the graphite to obtain a pulverized product.

The particle size of the pulverized product may be 7 to 50 탆.

Another embodiment provides an artificial graphite anode material for a lithium secondary battery produced by the method for manufacturing artificial graphite anode material for a lithium secondary battery.

The spacing d002 of the crystal faces of the artificial graphite anode material may be 3.354 to 3.365 angstroms, the lattice constant Lc may be 200 to 1000 angstroms, and the lattice constant La may be 700 to 2000 angstroms.

The details of other embodiments are included in the detailed description below.

A high-capacity artificial graphite anode material for a lithium secondary battery can be manufactured at a low manufacturing cost.

Fig. 1 is a photograph showing the appearance of the acicular coke masses used in Examples 1 to 4 and Comparative Example 1. Fig.
Figs. 2A and 2B are photographs of a polarizing microscope of the needle-shaped coke used in Examples 1 to 4 and Comparative Example 1, respectively, at magnifications of 200 magnifications and 500 magnifications.
FIGS. 3A and 3B are scanning electron microscope (SEM) photographs of artificial graphite anode materials for a lithium secondary battery according to Example 1 at magnifications of 5,000 and 10,000, respectively. FIG.

Hereinafter, embodiments of the present invention will be described in detail. However, it should be understood that the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

Artificial graphite, which is generally used as an anode material for a lithium secondary battery, is mainly produced by a coal-based pitch or a petroleum-based pitch produced through a carbonization process and a graphitization process. In this case, metal carbide is used as a graphitization catalyst. Despite the use of such a catalyst, graphitization at a high temperature of about 3000 ° C. is required to achieve a discharge capacity of 340 mAh / g or more in a commercialization process for application of a battery . Such a high-temperature heat treatment process may lead to an increase in manufacturing cost and thus a problem that the application market of artificial graphite is limited.

Also, the metal carbide has a particle size of usually 20 mu m or more. Their micronization can be achieved through a pulverization process, but it is difficult to apply them commercially because the pulverization yield is low. When the catalyst having such a large particle size is used, the contact area with the coke for progressing the catalytic graphitization reaction is relatively small, so that the proportion of graphite formed due to the catalytic graphitization is relatively decreased, The usage amount is increased.

In one embodiment, artificial graphite having a high degree of graphitization can be obtained even at a low graphitization temperature and a small amount of use by using a metal oxide or metal hydroxide as a fine particle as a catalyst. Thus, a high-capacity artificial graphite anode material can be produced even at a low manufacturing cost.

Specifically, the artificial graphite anode material for a lithium secondary battery according to an embodiment is obtained by mixing a coke and fine particles to obtain a mixture, subjecting the mixture to a first heat treatment to obtain a carbide, and then subjecting the carbide to a second heat treatment to obtain graphite . ≪ / RTI > The fine particles may include a metal oxide, a metal hydroxide, or a combination thereof. The metal used for the fine particles may include Ti, Ni, Al, Si, W, or a combination thereof.

The coke may be specifically an acicular coke or the like. The needle-like coke can be obtained by controlling the impurities, the molecular weight and the degree of structural orientation through the purification process of the coal-based coal tar or the petroleum residual oil generated during the coal drying process and then through the caulking process. The acicular coke is a coke having an anisotropic texture and is distinguishable from an isotropic coke having an isotropic structure.

The acicular coke contains ash in an amount of less than 0.01% by weight, volatile matter in an amount of 0.5% by weight, and fixed carbon in an amount of 99% by weight or more.

The coke may be pulverized to have an average particle diameter (D50) of 1 to 15 mu m, specifically, an average particle diameter (D50) of 3 to 7 mu m. When the average particle diameter (D50) of the coke is within the above range, the binder pitch can be used in a minimum amount in the production of a molded article, and a high-density molded article can be produced without requiring an excessive molding pressure.

When the fine particles are mixed together with the coke, the graphitization degree is increased even at a low graphitization temperature, so that a high-capacity artificial graphite anode material can be obtained at a low production cost.

The average particle size (D50) of the fine particles may be 1 to 45 탆, and may be 1 to 5 탆. When the fine particles have a small particle size within the above range, the contact area with the coke is large, so that a high degree of graphitization can be obtained as the ratio of graphite formed due to catalyst graphitization increases.

The fine particles may be specifically NiO, Ni ₂ O ₃ , NiOOH, Ni (OH) ₂ , corundum (Al ₂ O ₃ ), diaspore (α-AlO (OH)), boehmite ) (γ-AlO (OH) ), arc Ala child agent _{(akdalaite) (5Al 2 O 3} · H 2 O), gibbsite (gibbsite) (γ-Al ( OH) 3 + α-Al (OH) 3) , via light (bayerite) (α-Al ( OH) 3 + β-Al (OH) 3), Ti 2 O 3, TiO 2, TiO (OH) 2, SiO 2, Si (OH) 4, Si 2 O _{(OH) 6, Si 3 O} 2 (OH) 8, Si 4 O 3 (OH) 10, WO 2, WO 3, H 2 WO 4, (NH 4) 10 [H 2 W 12 O 42] · 4H 2 O, or a combination thereof.

The fine particles may be mixed so that the atomic ratio of the metal element contained in the coke and the fine particles is 100: 1 to 100: 30, and specifically 100: 2 to 100: 10. Even if the fine particles are used in a small amount within the above content range, a high-capacity artificial graphite anode material can be obtained as the degree of graphitization is increased.

When the coke and the fine particles are mixed, the binder pitch serving as the binder may be mixed together.

The binder pitch may be a pitch produced by purifying and polymerizing coal-based coal tar or petroleum residual oil. The binder pitch may have a softening point of 40 to 250 ° C, and may contain 0.1 to 5% by weight of a quinoline insoluble matter.

The mixing step may be performed by liquid phase mixing, dry mixing or the like.

The binder pitch may be 5 to 50 parts by weight based on 100 parts by weight of the coke, and specifically 25 to 35 parts by weight. When the binder pitch is mixed within the above content range, the density of the molded body using the mixture of coke, fine particles, and binder can be increased, and the capacity drop of the finally manufactured negative electrode material can be minimized through proper usage. This is because the capacity of the graphitized part of the carbon resulting from the pitch is as low as 300 mAh / g or less.

Next, the molding process of the mixture may be performed before the carbonization process by heat treatment of the mixture.

Specifically, after the mixture is filled in a mold, a molded body can be manufactured through a press process. In this case, the molding pressure may be 100 to 250 MPa, and in particular 150 to 200 MPa. When the molding pressure is within the above range, it is easy to produce a molded body having a density of 1.4 g / cc or more and a molded body of high strength without cracks can be secured.

The molding step may be performed by a method such as uniaxial compression molding, cold isostatic pressing, extrusion molding, or the like.

Next, a carbonization process may be performed to carbonize the mixture or the mixture of the mixture by a first heat treatment.

The first heat treatment may be performed at a temperature of 800 to 1500 ° C, and more specifically, at a temperature of 900 to 1300 ° C. When the heat treatment for carbonization is performed within the temperature range, the amount of the fixed carbon is high and the amount of the sublimation component generated in the graphitization process can be reduced, which is preferable. In addition, when the heat treatment is performed within the above-mentioned temperature range, it is not necessary to include a facility equipped with a high temperature heating element required for heat treatment at a higher temperature.

The first heat treatment may be performed in an atmosphere containing nitrogen, argon, hydrogen, helium or a mixed gas thereof, or under a vacuum.

Next, the graphitization process for graphitizing the carbide obtained by the carbonization process by the second heat treatment may be performed.

The graphitization process may be performed in an induction heating system of Linn HIGH THERM GMBH, Germany, but is not limited thereto. In the induction heating method, it takes 30 minutes to 1 hour to increase the temperature to 2800 ° C.

The second heat treatment may be performed at a temperature of 2500 to 2800 ° C, specifically, at a temperature of 2500 to 2700 ° C, and more specifically, at a temperature of 2500 to 2600 ° C. When the heat treatment for graphitization is carried out within the above-mentioned temperature range, a high-capacity artificial graphite can be produced, thereby reducing the high manufacturing cost due to the high-temperature heat treatment process.

The second heat treatment may be performed in an atmosphere containing nitrogen, argon, hydrogen, helium or a mixed gas thereof, or under a vacuum.

The graphite obtained through the graphitization step is pulverized to obtain a pulverized product having an average particle size (D50) of 7 to 50 mu m, specifically, an average particle size (D50) of 10 to 30 mu m. When a crushed product of graphite having an average particle size (D50) within the above range is used as an anode material, a proper electrode density can be realized and a side reaction with the electrolyte can be reduced due to a small amount of the generated fine powder, have.

The pulverization may be performed by a pin mill, a jet mill or the like.

The artificial graphite anode material produced by the above-described production method can have a high degree of graphitization by increasing the degree of crystallization of carbon. Specifically, in the XRD analysis, d002 representing the interval of crystal planes may be 3.354 to 3.365 angstroms, specifically, 3.357 to 3.365 angstroms. Also, in the XRD analysis, the lattice constant L _C can be 200 to 1000 Å, specifically 300 to 700 Å. Also, in the XRD analysis, the lattice constant La may be 700 to 2000 Å, and more specifically 800 to 1800 Å. When the value of d002 has a small value within the range, and when the values of Lc and La have a large value within the range, a high degree of graphitization may be exhibited.

The artificial graphite anode material described above can secure a high capacity, and thus can be usefully used in a lithium secondary battery.

The lithium secondary battery includes an electrode assembly including a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode. The electrode assembly includes a sealing member that is housed in a battery container, impregnates the electrolyte, and seals the battery container.

The negative electrode may be prepared by preparing a composition for forming a negative electrode active material layer by mixing the above artificial graphite negative electrode material, a binder and optionally a conductive material, and then applying the composition to an anode current collector such as copper.

Examples of the binder include polyvinyl alcohol, carboxymethylcellulose / styrene-butadiene rubber, hydroxypropylene cellulose, diacetylene cellulose, polyvinyl chloride, polyvinylpyrrolidone, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene Polypropylene and the like can be used, but the present invention is not limited thereto.

The binder may be mixed in an amount of 1 to 30% by weight based on the total amount of the composition for forming the negative electrode active material layer.

The conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, and specifically includes graphite such as natural graphite and artificial graphite; Carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The conductive material may be mixed in an amount of 0.1 to 30% by weight based on the total amount of the composition for forming the anode active material layer.

The positive electrode may be prepared by mixing a positive electrode active material, a binder and optionally a conductive material to prepare a composition for forming a positive electrode active material layer, and then applying the composition to a positive electrode current collector such as aluminum.

As the cathode active material, a compound capable of reversibly intercalating and deintercalating lithium (a lithiated intercalation compound) can be used. Concretely, at least one of complex oxides of lithium and at least one kind selected from cobalt, manganese and nickel can be used.

The electrolyte solution may be a lithium salt and a non-aqueous organic solvent.

The lithium salt is _{LiCl, LiBr, LiI, LiClO 4} , LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiAlCl 4, CH 3 SO 3 Li, CF ₃ SO ₃ Li, (CF ₃ SO ₂ ) ₂ NLi, chloroborane lithium, lower aliphatic carboxylate lithium, lithium 4-phenylborate, and imide.

Examples of the non-aqueous organic solvent include N-methyl-2-pyrrolidone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma-butyrolactone, 1,2-dimethoxyethane, But are not limited to, ricifrcr, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, An ether, a methyl ethyl pyrophosphate, an ethyl propionate, a methyl ethyl ketone derivative, a methyl ethyl ketone derivative, a methyl ethyl ketone derivative, Etc. may be used.

The separator may be an olefin-based polymer such as polypropylene, which is chemically resistant and hydrophobic; A sheet or a nonwoven fabric made of glass fiber, polyethylene or the like can be used. When a solid electrolyte such as a polymer is used as the electrolytic solution, the solid electrolytic solution may also serve as a separation membrane.

Hereinafter, preferred embodiments and comparative examples of the present invention will be described. However, the following examples are only the preferred embodiments of the present invention, and the present invention is not limited by the following examples.

(Artificial graphite for lithium secondary batteries Anode material  Produce)

Example  1 to 4

The needle coke (ash content: less than 0.01 wt%) was pulverized through a jet mill into powder having an average particle diameter (D50) of 5 탆. The needle coke powder, the average particle diameter (D50) with this 3㎛ of TiO ₂ particles, and coal tar, or petroleum residue purified and polymerized to prepare a binder pitch (softening point of 40 to 250 ℃ a 0.1 to 5% by weight Of quinoline insoluble fraction) were mixed to obtain a mixed powder. At this time, the TiO ₂ particles were mixed so that the atomic ratio of the needle-like coke and the Ti element was in the range of 100: 2 to 100: 10 as shown in Table 1 below. The binder pitch was mixed in an amount of 30 parts by weight based on 100 parts by weight of the needle-like coke.

The mixed powder was filled in a molding mold, and a molded body was produced through a pressing process. The molding pressure was fixed at 100 MPa or more.

The mixed powder was heat-treated at 1300 ° C for 1 hour in an N ₂ atmosphere to obtain a carbide.

The carbide was heat-treated at 2500 ° C for 2 hours in an Ar gas atmosphere in an induction heating furnace of Linn HIGH THERM GMBH, Germany, and then naturally cooled to obtain graphite.

The graphite was milled through a pin mill and a jet mill process to produce artificial graphite having a particle size of 15 mu m.

Comparative Example  One

The needle coke (ash content: less than 0.01 wt%) was pulverized through a jet mill into powder having an average particle diameter (D50) of 5 탆. The acicular coke powder was heat-treated at 1300 캜 for 1 hour in an N ₂ atmosphere to obtain a carbide. The carbide was heat-treated at 3000 DEG C for 2 hours in an Ar gas atmosphere under the induction heating method of Linn HIGH THERM GMBH, Germany, and then naturally cooled to obtain graphite. The graphite was milled through a pin mill and a jet mill process to produce artificial graphite having a particle size of 15 mu m.

Comparative Example  2

Example 1 using the TiC 3㎛ the average particle diameter (D50) instead of TiO ₂ particles in and, wherein the TiC particles have an atomic ratio of 100 of needle coke and Ti: graphite were mixed such that the cargo 10, and heat-treated at 3000 ℃ , Artificial graphite was produced in the same manner as in Example 1.

Coke: The atomic ratio of Ti Graphitization temperature (캜) Example 1 100: 2 2500 Example 2 100: 5 2500 Example 3 100: 7 2500 Example 4 100: 10 2500 Comparative Example 1 100: 0 3000 Comparative Example 2 100: 10 3000

Rating 1: Needle coke  Photo analysis

Fig. 1 is a photograph showing the appearance of the acicular coke masses used in Examples 1 to 4 and Comparative Example 1. Fig. Figs. 2A and 2B are photographs of a polarizing microscope of the needle-shaped coke used in Examples 1 to 4 and Comparative Example 1, respectively, at magnifications of 200 magnifications and 500 magnifications.

Referring to FIG. 1, the needle coke used in Examples 1 to 4 and Comparative Example 1 was obtained by controlling impurities, molecular weight and structure orientation degree through a purification process of coal-based coal tar or petroleum residue, followed by a caulking process.

Referring to FIGS. 2A and 2B, it can be seen that the needle-shaped coke used for producing the artificial graphite anode material for a lithium secondary battery has an anisotropic texture.

Evaluation 2: Artificial graphite anode material SEM  Photo analysis

FIGS. 3A and 3B are scanning electron microscope (SEM) photographs of artificial graphite anode materials for a lithium secondary battery according to Example 1 at magnifications of 5,000 and 10,000, respectively. FIG.

3A and 3B, it can be seen that graphite particles are assembled in the artificial graphite produced in Example 1, and voids are formed in the granulation structure of the primary particles inside the particles . It is also confirmed that the orientations of the graphite particles are not parallel but randomly oriented.

Evaluation 3: Artificial graphite anode material Graphitization degree  analysis

Table 2 shows the results of X-ray diffraction (XRD) analysis in order to evaluate the degree of graphitization of the artificial graphite anode materials produced in Examples 1 to 4 and Comparative Example 1.

XRD analysis was performed under the following conditions.

Slit Condition: Divergence Silt, Scattering Slit 0.5 °, Receiving Slit 0.15mm

X-ray wavelength: 1.541838 Å (Cu Kαm)

Scan conditions: 0.02 step, 1 DEG / min

d002 (A) Lc (A) La (A) Example 1 3.365 329 807 Example 2 3.441 723 1589 Example 3 3.357 557 1735 Example 4 3.357 590 1750 Comparative Example 1 3.366 343 612 Comparative Example 2 3.365 346 780

In Table 2, d002 represents the interval of crystal planes in XRD analysis, and Lc and La represent lattice constants in XRD analysis.

As shown in Table 2, artificial graphite of Examples 1 to 4 obtained by mixing acicular coke and fine metal oxide particles had a small d002 value and a large value of Lc and La as compared with Comparative Example 1, Is increased.

In addition, the graphite of Examples 1 to 4 exhibited a higher degree of graphitization than that of Comparative Example 1 in which graphitization was carried out at 3000 ° C without using fine metal oxide particles, even though graphitization proceeded at 2500 ° C.

Also, referring to Examples 1 to 4, it can be seen that the degree of graphitization is increased as the amount of Ti added increases.

Also, in the case of Comparative Example 2, it can be confirmed that although the TiC catalyst was used, the degree of crystallinity was almost similar to that of Comparative Example 1 in which no catalyst was used. From this, it can be seen that the catalytic graphitization effect is almost not obtained when using the carbide of Ti, and in the case of Ti metal, the catalytic graphitization effect is more excellent when it is used in the oxide or hydroxide form rather than the carbide.

Evaluation 4: Capacity and efficiency analysis of lithium secondary battery

Artificial graphite and polyvinylidene fluoride (PVdF) prepared in Examples 1 to 4 and Comparative Example 1 as negative electrode active materials were added to N-methylpyrrolidone (NMP) solvent at a weight ratio of 95: 5 to prepare a slurry . The slurry was applied to a copper foil, dried, and roll pressed to produce a negative electrode. A coin half cell was fabricated using the negative electrode and a lithium metal as its counter electrode and using a separator made of polyethylene. At this time, the electrolytic solution composition was prepared by dissolving LiPF ₆ in a mixed solvent of ethylene carbonate (EC) and dimethyl carbonate (DMC) in a volume ratio of 3: 7.

The cells were charged and discharged under the following conditions, and the results are shown in Table 3 below.

Charging: 0.1C-rate, CC / CV mode, 0.01V / 0.01C cutoff

Discharge: 0.1C-rate, CC mode, 1.5V cut-off

Initial charge capacity (mAh / g) Initial discharge capacity (mAh / g) Charging / discharging efficiency (%) Example 1 361.3 326.5 90.4 Example 2 374.5 344.7 92.0 Example 3 382.3 353.6 92.5 Example 4 383 350.5 91.5 Comparative Example 1 356.2 303.7 85.3 Comparative Example 2 350.2 300.2 85.7

In Table 3, the charge-discharge efficiency (%) is obtained as a percentage of the initial charge capacity versus the initial charge capacity.

From Table 3, it can be seen that Examples 1 to 4, in which artificial graphite obtained by mixing needle-like coke and fine metal oxide particles together as an anode material for a lithium secondary battery, can secure a high capacity.

Also, referring to Examples 1 to 4, it can be seen that as the amount of addition of Ti element increases, the degree of graphitization increases and thus the charge / discharge capacity increases.

In Comparative Example 1 in which no catalyst was used and Comparative Example 2 in which TiC was used as a catalyst, the discharge capacity and the charge / discharge efficiency were lower than those of Examples 1 to 4 despite the graphitization at a higher temperature.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And it goes without saying that the invention belongs to the scope of the invention.

Claims (18)

Mixing the coke and the fine particles to obtain a mixture;
Subjecting the mixture to a first heat treatment to obtain a carbide; And
And subjecting the carbide to a second heat treatment at a temperature of 2500 to 2800 ° C to obtain graphite,
Wherein the microparticles comprise a metal oxide, a metal hydroxide, or a combination thereof, wherein the metal comprises Ti, Ni, Al, Si, W,
Method for manufacturing artificial graphite anode material for lithium secondary battery.
The method according to claim 1,
Wherein the coke comprises an acicular coke containing less than 0.01% by weight of ash.
The method according to claim 1,
Wherein the average particle diameter (D50) of the coke is 1 to 15 mu m.
The method according to claim 1,
Wherein the fine particles have an average particle diameter (D50) of 1 to 45 mu m.
The method according to claim 1,
The fine particles may be selected from the group consisting of NiO, Ni ₂ O ₃ , NiOOH, Ni (OH) ₂ , corundum (Al ₂ O ₃ ), diaspore (α-AlO γ-AlO (OH)), arc Ala child agent _{(akdalaite) (5Al 2 O 3} · H 2 O), gibbsite (gibbsite) (γ-Al ( OH) 3 + α-Al (OH) 3), via Light (bayerite) (α-Al ( OH) 3 + β-Al (OH) 3), Ti 2 O 3, TiO 2, TiO (OH) 2, SiO 2, Si (OH) 4, Si 2 O (OH _{) 6, Si 3 O 2 (} OH) 8, Si 4 O 3 (OH) 10, WO 2, WO 3, H 2 WO 4, (NH 4) 10 [H 2 W 12 O 42] · 4H 2 O or And a combination thereof. ≪ RTI ID = 0.0 > 11. < / RTI >
The method according to claim 1,
Wherein the fine particles are mixed such that the atomic ratio of the coke and the metal element contained in the fine particles is 100: 1 to 100: 30.
The method according to claim 1,
Wherein the mixture is obtained by further mixing a binder pitch.
8. The method of claim 7,
Wherein the binder pitch has a softening point of 40 to 250 캜 and a quinoline insoluble content of 0.1 to 5% by weight.
8. The method of claim 7,
Wherein the binder pitch is 5 to 50 parts by weight based on 100 parts by weight of the coke.
The method according to claim 1,
Before the first heat treatment of the mixture,
Molding the mixture
Wherein the graphite negative electrode material is a graphite negative electrode material.
The method according to claim 1,
Wherein the first heat treatment is performed at a temperature of 800 to 1500 ° C.
delete The method according to claim 1,
After obtaining the graphite,
And crushing the graphite to obtain a pulverized product
Wherein the graphite negative electrode material is a graphite negative electrode material.
14. The method of claim 13,
Wherein the average particle size (D50) of the pulverized product is 7 to 50 占 퐉.
An artificial graphite anode material for a lithium secondary battery produced by the method of any one of claims 1 to 11, 13, and 14.
16. The method of claim 15,
Wherein an interval d002 of crystal faces of the artificial graphite anode material is 3.354 to 3.365 angstroms.
16. The method of claim 15,
Wherein the artificial graphite anode material has a lattice constant Lc of 200 to 1000 ANGSTROM.
16. The method of claim 15,
Wherein the artificial graphite anode material has a lattice constant La of 700 to 2000 ANGSTROM.

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